The proposed research program focuses on effects of the growth environment on the production of lactic acid and dextransucrase by Streptococcus mutans. Continuous microbial culture is used as a tool to control the growth rate of S. mutans in defined environments. Particular attention is directed toward effects of different growth-limiting nutrients, e.g. nitrogen, carbon, phosphate on acid and enzyme production. These studies are concerned with the behavior of S. mutans in slow growing, steady state environments and under transient conditions induced by a rapid nutritional shift-up. Under steady state conditions, the production of lactic acid is greatly affected by the nature of the growth-limiting nutrient; phosphate-limited growth leads to a large overproduction of lactate. Current work with non-steady state growth also indicates that after a nutritional shift-up there is an overproduction of lactic acid. Studies on dextransucrase production have demonstrated the importance of the nitrogen source, pH, and carbon source in regulating enzyme production. Future work is focused on developing a better quantitative understanding of how environmental o parameters affect the production of this enzyme.